[Macroscopic and microscopic appearance of arterial stumps in limb segment amputation]

Until now, it has been assumed that in arterial lesions invagination of the intimal layer occurs. In a thigh and an upper-arm amputation this assumption was scrutinized. No hemorrhage or hypovolemic shock occurred in either case despite total amputation. The brachial and femoral arteries were closed and pulsed visibly within the soft tissue. Histology showed no invagination: the adventitial layer was drawn over the open lumen, which was filled with an extensive thrombus. Therefore, in these cases occlusion of the artery is presumed to occur by means of a fingertrap mechanism of the adventitia and the interaction of collagenous fibers with platelets. This hypothesis will be tested in an animal experiment.

Cardiopulmonary baroreflex control of brachial artery diameter in sustained essential hypertension

An exaggerated reflex response of forearm resistance vessels following stimulation of cardiac mechanoreceptors has been observed in human hypertension. In the present study we analyze the possibility that such an increased response also involves the large brachial artery. For that purpose, the influence of leg elevation in subjects in a supine position on brachial artery diameter and blood flow velocity was studied in 12 healthy, normal males and 17 males of the same age with sustained essential hypertension. Brachial artery diameter and blood flow velocity were measured using a two-dimensional pulsed Doppler velocimeter, with subjects in a supine horizontal position, after passive elevation of the legs and again in a supine horizontal position. Blood pressure and heart rate remained unchanged throughout the study. Elevation of the legs induced an immediate increase in brachial artery diameter (P less than 0.001) and blood flow velocity (P less than 0.001) in both normal subjects and hypertensive patients. The maximal increase in these two parameters was similar in the two groups. In normal subjects, the increases were short-lived, with values returning to baseline levels even when leg elevation was maintained. In hypertensive patients, the increases persisted throughout the period of leg elevation, and brachial artery diameter remained significantly increased in comparison with normal subjects (P less than 0.01). This study provides evidence that loading cardiac mechanoreceptors causes a large dilation of the conduit arteries which is long-lasting in essential hypertensives and short-lived in normal subjects.

[Shearing anomalies of the arterial endothelium in essential arterial hypertension]

Brachial artery wall shear rate and stress were studied in 20 untreated hypertensive patients and 11 normotensive controls of similar age. A pulsed Doppler velocimeter enabled to determine the internal diameter, the mean cross-sectional blood velocity and the systolic centerline blood velocity of the brachial artery. A coaxial cylinder viscosimeter provided blood viscosity at a shear rate of 96 s-1. A Poiseuille model of arterial flow was used for evaluating wall shear rate from the ratio between blood velocity and arterial diameter and wall shear stress from the product between shear rate and blood viscosity. Shear rate and stress were expressed in terms of systolic and mean values by using respectively systolic centerline and mean cross-sectional blood velocities. Comparatively to normal controls, hypertensive patients had higher blood viscosity (4.80 +/- 0.08 vs 4.28 +/- 0.09 cpoise, p less than 0.001) lower systolic wall shear rate (303 +/- 18 vs 413 +/- 20 s-1, p less than 0.001), lower mean wall shear rate (70 +/- 6 vs 109 +/- 16 s-1, p less than 0.01) and lower systolic wall shear stress (13.86 +/- 0.81 vs 17.02 +/- 1.26, p less than 0.001) but mean wall shear stress was not statistically different between patients and controls. Such wall shear abnormalities are described for the first time in large artery of hypertensive patients and merit attention because of the experimental critical role of low shear conditions on the atherogenic process.

[Flow-dependent vasodilation of the brachial artery in the normotensive and essential hypertensive patient]

Brachial artery hemodynamics including brachial artery diameter (D), local blood flow velocity (V) and local volumic blood flow, was studied in 10 normotensive subjects (NT) and 10 age-matched hypertensive patients (HT) (50 +/- 4 vs 43 +/- 4 years; m +/- SEM; NS), using a bidimensional pulsed doppler system at rest (control period), during a 2 (or 4) mn-period of distal circulatory occlusion (DO) and during the following reactive hyperemia (RH). Kinetics of change in blood flow velocity and diameter were determined during successive and reproducible manoeuvres. V and D decreased significantly during DO. During RH (1) V reached similar maximum values in both groups (after 2 mn DO: NT: from 2.4 +/- 1.1 to 19.0 +/- 6.9 cm/s; HT: from 2.9 +/- 0.8 to 17.2 +/- 7.6 cm/s) and (2) D increased significantly in both groups (after 2 mn DO: NT: from 0.395 +/- 0.016 to 0.450 +/- 0.025 cm; p less than 0.001; HT: from 0.408 +/- 0.018 to 0.467 +/- 0.018 cm; p less than 0.001), reaching levels significantly higher than during the control period. The brachial artery vasodilation observed in both groups (NT: +12 +/- 3 p. 100; HT: +15 +/- 3 p. 100 of initial diameter) was significantly greater (p less than 0.001), than the reproducibility of the diameter measurement (3 +/- 1 p. 100). Mean arterial pressure and heart rate dit not change during the whole investigation. Increasing the duration of DO from 2 to 4 mn further enhanced the reactive blood flow velocity but did not change the magnitude of the reactive brachial artery vasodilation.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of age on brachial and carotid circulation in human arterial hypertension]

Right brachial artery and common carotid artery haemodynamic parameters were studied using pulsed Doppler velocimetry enabling non invasive measurements of their internal diameters and blood velocities in 74 untreated essential hypertensive patients subdivided in two groups of younger than (33 patients) and older than 45 years (41 patients). There were no significant differences in the haemodynamic parameters of brachial artery (i.e. diameter and blood velocity) between the two groups of patients. In the patients older than 45, there were no changes in the diameter of common carotid artery, but there was a decrease in carotid artery blood velocity as compared with patients younger than 45 (p less than 0.001). In the patients younger than 45, there were no correlations between the haemodynamic parameters of both circulations; in contrast, in patient older than 45 significant relationship were found between the common carotid artery diameter and the brachial artery diameter (r = 0.45, p less than 0.01) and between the blood velocity in the common carotid artery and in the brachial artery (r = 0.55, p less than 0.001). Thus, in these hypertensive patients, brachial artery circulation was not affected by age; but age older than 45 was associated with a decrease in common carotid blood flow, with no change in common carotid artery diameter. However, the existence of strong correlations between brachial and carotid artery diameters and blood velocities in patients older than 45, suggests that age might interfere, in hypertensive patients, with the specific regulatory adjustments of the brachial and carotid circulations.

Combined effects of gender and hypertension on the geometric design of large arteries. Sexual differences in normal and hypertensive forearm arteries

The effects of sex, hypertension, morphologic status, and heart rate were assessed on the large arteries of 46 normotensive subjects (23 men and 23 women) and 50 hypertensive patients (25 men and 25 women) by means of pulsed Doppler determination of diameter and blood velocity of the brachial artery. Compared to men, women had lower height, weight, and forearm volume (P less than 0.001), higher heart rate (P less than 0.001), and lower brachial artery diameter (P less than 0.001) both in the normotensive and hypertensive groups. Compared to normotensives, hypertensives of the same sex showed an increase in brachial artery diameter, only significant in men (P less than 0.001), and an increase in heart rate, only significant in women (P less than 0.001). The multiple regression analysis of brachial artery diameter showed significant coefficients for sex and hypertension (P less than 0.001), and for age and heart rate (P less than 0.05); the multiple regression analysis of blood velocity showed that only the coefficient of hypertension was significant (P less than 0.05). The study of first-order interactions between the independent variables revealed that effect of sex on arterial diameter did not depend on the other variables. In contrast the effects of age and heart rate were influenced by the presence or the absence of hypertension, and arterial caliber was positively related to age in normotensive subjects (P less than 0.05) but not in hypertensive patients, and negatively related to heart rate in hypertensive patients (P less than 0.001) but not in normotensive subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Stable improvement in large artery compliance after long-term antihypertensive treatment with enalapril

In 12 patients with mild or moderate essential hypertension we assessed by 2-D pulsed Doppler flowmetry the influence of a 6-month effective treatment with enalapril or atenolol on peripheral hemodynamics. The patients were studied in control conditions, at the end of the 6-month pharmacologic treatment, and 2 weeks after the withdrawal of the therapy. In spite of a comparable fall in blood pressure, the effects of the two drugs on forearm hemodynamics were quite different. Enalapril induced a fall in vascular resistance and an increase in brachial artery diameter, flow, and compliance, while atenolol failed to modify all these parameters. In the enalapril group the improvement in forearm vascular resistance and brachial artery compliance persisted after the 2-week washout period. This latter observation raises the possibility that enalapril may reverse structural changes in the large arteries.

Combined effects of sex and hypertension on the geometrical design of large arteries. Sexual differences in normal and hypertensive forearm arteries

The effects of sex, hypertension, morphological status, and heart rate were assessed on the large arteries of 46 normotensive subjects (23 men and 23 women) and 50 hypertensive patients (25 men and 25 women) by means of pulsed Doppler determination of diameter and blood velocity of the brachial artery. Compared with men, women had lower height, weight, and forearm volume (p less than 0.001), higher heart rate (p less than 0.001), and lower brachial artery diameter (p less than 0.001), both in the normotensive and hypertensive groups. Compared with normotensive subjects, hypertensive patients of the same sex showed an increase in brachial artery diameter (only significant in men [p less than 0.001]) and an increase in heart rate (only significant in women [p less than 0.001]). The multiple regression analysis of brachial artery diameter showed significant coefficients for sex and hypertension (p less than 0.001) and for age and heart rate (p less than 0.05); the multiple regression analysis of blood velocity showed that only coefficient of hypertension was significant (p less than 0.05). The study of first-order interactions between the independent variables revealed that effect of sex on arterial diameter did not depend on the other variables. In contrast, the effects of age and heart rate were influenced by the presence or the absence of hypertension, and arterial caliber was positively related to age in normotensive subjects (p less than 0.05) but not in hypertensive patients and negatively related to heart rate in hypertensive patients (p less than 0.01) but not in normotensive subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Thromboangiitis obliterans affecting the upper extremity in a woman. Case report

A rare case of thromboangiitis obliterans is reported, with involvement of the left brachial and axillary artery and signs of median-nerve denervation in a 42-year-old woman following long affection of the right popliteal artery. Arterial reconstruction of the upper extremity was beneficial when the patient stopped smoking. The histologic changes distinguished the condition from atherosclerosis.

Brachial artery cross-sectional area and distensibility before and after arteriolar vasodilatation in men with sustained essential hypertension

Blood pressure, volume distensibility (VD), and cross-sectional area (CSA) of the brachial artery were studied using pulsed Doppler systems in 51 patients with sustained essential hypertension in comparison with 21 normotensive controls of the same age. In hypertensive patients, in baseline conditions, CSA was significantly increased and VD decreased--the two parameters strongly and negatively correlated independent of the blood pressure level. Arteriolar vasodilatation was produced by three pharmacological agents--cadralazine, a dihydralazine-like compound; nicorandil, a nicotinamide derivative; and nitrendipine, a calcium entry blocker. For the same blood pressure reduction, cadralazine significantly reduced CSA, while nicorandil and nitrendipine increased it. Nitrendipine significantly increased VD, which was not modified by cadralazine and nicorandil. For cadralazine and nicorandil, a significant negative correlation was observed between VD and CSA. The relationship was the same as in baseline conditions. With nitrendipine, no significant correlation was observed between the two parameters. At any given CSA, distensibility was higher with nitrendipine than with cadralazine or nicorandil. The study provided evidence that, in men with essential hypertension, in basal conditions, the negative relationship between VD and CSA reflected intrinsic alterations of the arterial wall, while cadralazine, nicorandil, and nitrendipine caused a similar degree of arteriolar dilatation, nicorandil and nitrendipine caused active arterial dilatation as well, and changes in distensibility after drug administration were not directly related to blood pressure level and were mediated either by predominant geometrical modifications (cadralazine, nicorandil) or by the predominant relaxing effect of the drug on arterial smooth muscle tone (nitrendipine), or both.

Histological and morphometric observations on the reticular fibers in the arterial beds of patients with ruptured intracranial saccular aneurysms

Histological and morphometric studies on the collagenous, reticular, and elastic fibers of the tunica media were performed on the middle cerebral and brachial arteries of patients with ruptured intracranial saccular aneurysms and controls. There was no difference between aneurysm patients and controls in the amount of collagenous and elastic fibers. The amount of reticular fibers was, however, reduced about 35% in aneurysm patients within both the middle cerebral artery (P less than 0.01) and the brachial artery (P less than 0.02). The reticular fibers were irregularly distributed and often appeared shorter and coarser than normally. The observations point to a generalized abnormality of the arterial bed in some patients with rupture of saccular aneurysms.

Thrombosis following percutaneous radial artery cannulation

A prospective study of the arterial supply of the hand was carried out in 100 ICU patients after cannulation of the radial artery. Patency of the radial artery was checked using a reversed Allen's test and Doppler ultrasonic technique. Furthermore, radial artery angiography was carried out in 15 patients with suspect thrombosis, and the artery was examined by microscopy in four patients at autopsy. Signs of thrombosis, Allen's test and Doppler technique, were found in 33/100 patients. In 10/15 angiograms a thrombosis was visualized, and in 3/4 patients at autopsy a thrombosis was found. The incidence of thrombosis was not correlated to sex, age, size of artery (judged by wrist circumference), cannulation technique or the presence of hypotension. It did, however, correlate to the presence of haematoma at the puncture site. After removal of the cannula recanalisation occurred soon in the majority of cases.

Common carotid blood flow in patients with hypertension and stenosis of the internal carotid artery

Common carotid blood flow has been measured using pulsed Doppler techniques in hypertensive patients over 45 years of age, with and without stenosis of the internal carotid artery. In hypertensive patients without stenosis, arterial diameter remained within the normal range, whereas blood flow velocity and blood flow were significantly reduced. Vascular resistance was significantly increased but did not change markedly after administration of the vasodilating drug isosorbid dinitrate. Patients with hypertension and stenosis of the internal carotid artery were compared with two different populations used as controls: In comparison with hypertensive patients without stenosis of the internal carotid artery, both arterial diameter and blood flow velocity were reduced, leading to a more pronounced decrease in blood flow; and in comparison with normotensive patients with stenosis of the internal carotid artery, common carotid blood flow was more reduced at any degree of stenosis. In a subset of patients, blood flow returned toward normal ranges after endarterectomy. The study suggested that in patients with hypertension without stenosis of the internal carotid artery, the decrease in blood flow is due to a decrease in blood flow velocity with normal arterial diameter despite the elevated blood pressure, and in patients with hypertension and stenosis of the internal carotid artery, blood flow was more reduced than in the normotensive patients with stenosis of the internal carotid artery, suggesting that caution must be taken with indications of antihypertensive treatment.

Large saccular aneurysm and A-V fistula of the brachial vessels

This paper reports a 39-year-old patient who developed an unusually large saccular false aneurysm and A-V fistula of the brachial vessels following a neglected penetrating wound. Rapid enlargement to 15 cm appeared after one year and the aneurysm was then stable for the six months prior to operative repair. The aneurysm was excised and lateral closure of the vessels restored continuity with uneventful recovery.

Onchocerca armillata: prevalence and pathology in Sudanese cattle

Cattle of various ages from Khartoum Province and western Sudan were surveyed for Onchocerca armillata infection by skin snip examination and some also at post-mortem examination. The former method reliably detected infection in cattle aged between nine months and eight years. Several of the older infected animals had no microfilariae in their skin. Prevalence rate and number of microfilariae per gram of skin were higher in male than in female cattle and in animals from western Sudan than those from Khartoum province. Severe pathological changes were seen in the thoracic aorta, brachiocephalic, costocervical and brachial arteries and posteriorly in the abdominal aorta to its bifurcation into the iliac arteries.

Course of the post-catheterization pulseless arm

With the purpose of determining the course of the non-operated post-catheterization brachial artery thrombosis, 45 patients in this condition were followed during a one month period of survey. A gradual increase in Doppler-derived pressure index of the ischemic arm was observed. This index averaged 0.51 on the day of occlusion, increased to an average of 0.66 in the immediate following day and on the 30th day averaged 0.82. All but 10 patients were asymptomatic after 30 days, although a similar increase in pressure index was observed among these patients, being thus indistinguishable from the whole group. Since it was not possible to predict in which patients symptoms of arm ischemia would remain present, it seems advisable to consider surgical restoration of flow in all cases of brachial artery thrombosis after cardiac catheterization.

Vascular pathogenesis of transverse limb reduction defects

Evaluation of four patients with unilateral transverse limb reduction defects indicates that some instances of this structural defect may be the result of an in utero vascular accident. Three of the four patients had microscopic evidence of fetal vascular occlusive disease on multiple sections of the placenta, suggesting that occlusion of the brachial artery was secondary to embolization from the placental vascular thrombi. The fourth, a 116 mm crown-rump long fetus, had a massive thrombus occluding the brachial artery, which was felt secondary to hypovolemia and hypoperfusion associated with fetal blood loss during placental abruption. Recognition of the disruptive vascular pathogenesis of some cases of unilateral transverse limb reduction defects explains their negligible recurrence risk. In such cases attention should be focused on careful gross and, microscopic evaluation of the placenta.

Dislocation of the median nerve and brachial artery in supracondylar fractures of the humerus

Two patients are described in whom the median nerve was dislocated and incarcerated between the fragments of a supracondylar fracture of the humerus. In one, the brachial artery was similarly incarcerated and was in spasm. In the second, the brachial artery had been ruptured by the upper fragment. Circulation was restored by operation in both instances. The mechanism of dislocation is discussed.

The surgical management of catheter injuries of the brachial artery

In 84 patients the wrist pulses were lost after diagnostic left heart catheterization via the brachial artery. Sixty-six of these patients underwent surgical exploration of the brachial artery for restoration of pulsatile arterial flow to the hand. This aim was achieved in 64 instances. In all cases, the artery was found to be occluded by fresh thrombus. In 36 patients, balloon thrombectomy and accurate arterial closure were successful. In the remainder, in addition to thrombectomy, indentification of an area of damage to the arterial wall required additional surgical measures, usually in the form of resection and anastomosis. The surgical approach to this problem and the importance of the recognition and treatment of arterial wall damage by the catheter are stressed in this paper.